tbuckley/cabot-search huggingface dataset:
STEM-16. MACROH2A2 REPRESSES AN EPIGENETIC SELF-RENEWAL NETWORK IN GLIOBLASTOMA STEM CELLS
Authors: Ana Nikolic, Anna Bobyn, Francesca Maule, Katrina Ellestad, Seungil Paik, Sajid Marhon, Parinaz Mehdipour, Xuequng Lun, Michael Johnston, Christopher Gafiuk, Franz Zemp, Yaoqing Shen, Nicoletta Ninkovic, Elodie Labit, N Daniel Berger, Duncan Brownsey, John Kelly, Jeff Biernaskie, Peter Dirks, Darren Derksen, Steven J M Jones, Donna L Senger, Jennifer Chan, Douglas J Mahoney, Daniel de Carvalho, Marco Gallo
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma is a highly malignant tumour driven by a subset of self-renewing cells termed glioblastoma stem cells. This self-renewal phenotype is largely epigenetically driven, however, the exact epigenetic mechanisms underpinning it are poorly understood. We found that the histone variant macroH2A2 is repressed in a subset of glioblastoma tumours, and that this repression is associated with poorer survival. We interrogate the function of macroH2A2 using in vitro and in vivo patient-derived models. We show that macroH2A2 antagonizes self-renewal and expression of NPC and OPC-like markers, and rewires accessible chromatin by maintaining accessibility at a subset of enhancer elements. We identify small molecules that can upregulate macroH2A2 expression, and find that treatment with a small molecule reduces self-renewal, induces interferon sensitive genes, and a viral mimicry response, effects which are abolished by macroH2A2 knockdown. In summary, we identify macroH2A2 as a repressor of self-renewal in glioblastoma and suggest it may be a novel biomarker and potential marker of therapeutic susceptibility.
INNV-12. REPRODUCIBLE REDUCTIONS OF CONTRAST-ENHANCED TUMOR VOLUMES IN TWO END-STAGE RECURRENT GLIOBLASTOMA PATIENTS WITH IN-HOME ONCOMAGNETIC MONOTHERAPY
Authors: Santosh Helekar, David Baskin
Journal: Neuro-Oncology (2022)

Abstract A spinning oscillating magnetic field-generating device called the Oncomagnetic device selectively kills glioblastoma (GBM) cells. It produced &amp;gt; 30% shrinkage of a recurrent GBM tumor in an end-stage patient after &amp;lt; 5 weeks of Oncomagnetic treatment (OMT). We have now reproduced this treatment response with additional insights into device effectiveness in two more such patients undergoing compassionate use OMT. We provided OMT to a 55-year-old man with massive recurrent tumor regrowth and a 79-year-old woman with multifocal recurrent GBM showing rapid progression, with leptomeningeal spread in both cases. Both had failed standard of care chemoradiotherapy and in the former case had not tolerated Optune treatment. They received one 2-hour, two 2-hour and three 2-hour OMTs per day in the clinic on the first three days under the supervision of the treating physician. 3 2-hour daily treatments were continued subsequently at home. The first patient received a steroid drug along with OMT to control cerebral edema from the start. In the second patient it was added after 14 days while also reducing OMT to 2 hours a day because of significant evidence of edema. MRI scans were done periodically to assess the treatment response. Both patients tolerated OMT well with no serious adverse effects – for 7 months in the first patient, including four 2-hour treatments for the last 5 months, and for 2 months in the second patient. Their last MRI scans at Day 146 and Day 42 showed &amp;gt; 35% and &amp;gt; 91% reduction, respectively, in contrast-enhanced tumor volume compared to pre-OMT scans. A modified treatment response assessment mapping analysis showed substantial reductions in both necrotic and active tumor volumes. These findings strongly support the observations in our published single patient case report and provide firm grounds for proposing in-home OMT monotherapy as a safe and effective noninvasive treatment for GBM.
EPID-11. NATIONAL EPIDEMIOLOGY AND SURVIVAL OF ADULT-TYPE DIFFUSE GLIOMAS IN THE UNITED STATES BY IDH, 1P/19Q, MGMT, AND WHO CNS GRADE
Authors: Bryan Iorgulescu, Chuxuan Sun, Gino Cioffi, Corey Neff, Madison Shoaf, Kristin Waite, Carol Kruchko, Patrick Y Wen, Daniel Brat, Quinn Ostrom, Jill Barnholtz-Sloan
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Histomolecularly-defined adult-type diffuse gliomas—including IDH-wildtype glioblastoma, IDH-mutant astrocytoma, and IDH-mutant 1p/19q-codeleted oligodendroglioma—were incorporated into U.S. cancer registry reporting for individuals with brain tumors beginning in 2018. We therefore assessed their epidemiology and overall survival (OS) patterns. METHODS Individuals histopathologically diagnosed with diffuse gliomas in 2018 and had brain molecular marker data were identified within the National Cancer Database; Surveillance, Epidemiology, and End Results Incidence; and Central Brain Tumor Registry of the United States databases. Age-adjusted incidence rates per 100,000 population with 95% confidence intervals (95CI) were estimated. OS was estimated using Kaplan Meier methods and stratified by WHO CNS grade, age, sex, tumor size, treatment, extent of resection, and MGMT promoter methylation. WHO CNS grade was additionally examined among individuals with IDH-wildtype diffuse astrocytic gliomas. RESULTS IDH-wildtype glioblastomas’ incidence rate was 1.74 (95CI = 1.69-1.78); as compared to 0.14 (95CI = 0.12-0.15), 0.15 (95CI = 0.14-0.16), and 0.07 (95CI: 0.06-0.08) WHO grade 2, 3, and 4 IDH-mutant astrocytomas. Irrespective of grade, IDH mutation prevalence was highest in adolescents &amp; young adults, and IDH-mutant astrocytomas were more frequently MGMT promoter methylated. For OS analysis, 8,651 individuals were identified: one-year OS was 53.7% for WHO grade 4 IDH-wildtype glioblastomas (95CI = 52.5-54.9); 98.0% (95CI = 96.1-99.0), 92.4% (95CI = 89.6-94.5), and 76.3% (95CI = 70.1-81.3) for grade 2, 3, and 4 IDH-mutant astrocytomas; 97.9% (95CI = 95.9-98.9) and 94.4% (95CI = 90.9-96.6) for grade 2 and 3 IDH-mutant 1p/19q-codeleted oligodendrogliomas. Among IDH-wildtype glioblastomas, median OS was 17.1 months (95CI = 16.1-18.6) and 12.4 months (95CI = 12.0-12.9) for methylated and unmethylated MGMT promoters. IDH-wildtype diffuse astrocytic gliomas reported as WHO grade 2 or 3 demonstrated longer adjusted OS compared to grade 4 tumors (both p &amp;lt; 0.001). A significant association was not observed between chemotherapy and OS (HRadjusted 0.95, 95CI = 0.41-2.22, p = 0.91) for radiotherapy-treated grade 3 IDH-wildtype diffuse astrocytic gliomas. CONCLUSIONS Our findings provide the initial U.S. epidemiological estimates for histomolecularly-defined adult-type diffuse gliomas.
QLTI-08. SURVEY OF CANADIAN NEURO-ONCOLOGY CLINICIANS ABOUT THE TREATMENT OF ADULT MEDULLOBLASTOMA
Authors: Seth Climans, Chantel Cacciotti, Mary Jane Lim-Fat
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Given the rarity of medulloblastoma in adults (fewer than 50 incident cases annually across Canada), the optimal chemotherapy strategy in this population is unknown. The management of adult medulloblastomas is thought to vary from institution to institution. Guidelines often omit suggestions for specific chemotherapy regimens, reflecting the lack of high quality evidence in this population. We sought to understand Canadian adult medulloblastoma practice patterns, hoping to inform future quality metrics and guidelines. METHODS In March 2022 a 30-question survey was sent out to 71 adult neuro-oncology clinicians on the Canadian Adolescent and Young Adult national rounds mailing list. Snowball sampling was permitted. RESULTS There were 25 responses (up to 35% response rate). Radiation oncologists (11), neuro-oncologists (8), medical oncologists (4), and neurosurgeons (2) responded from 6/10 Canadian provinces. They each treated on average 1.6 medulloblastoma patients per year. Most (61% of respondents) said that medulloblastoma molecular subgrouping was always done at their centre. Half (50%) indicated that cerebrospinal fluid testing was always done at diagnosis. The most common (64%) radiation regimen was 36 Gy (in 20 fractions) craniospinal irradiation + 18 Gy (in 10 fractions) boost. Concomitant chemotherapy was rarely given (75% of respondents included chemotherapy less than half of the time). Adjuvant chemotherapy was frequently administered (79% of respondents give it more than half of the time). The most common adjuvant chemotherapy was Cisplatin/Lomustine/Vincristine (57%), but other regimens included Cisplatin/Lomustine/Vincristine alternating with Cyclophosphamide/Vincristine (21%), Cisplatin/Cyclophosphamide/Vincristine (14%), and carboplatin-based regimens (14%). Respondents noted challenges prescribing chemotherapy in this population: drug toxicities, limited resources, and clinical uncertainty. There was support for standard of care adult medulloblastoma guidelines in 92% of respondents. CONCLUSIONS There is significant practice variation among Canadian neuro-oncology centres treating adult medulloblastoma. This variation can serve as an opportunity for quality improvement and clinical research.
NIMG-84. PREDICTION OF RESPONSE TO LOMUSTINE-BASED CHEMOTHERAPY IN GLIOMA PATIENTS AT RECURRENCE USING MRI AND FET PET
Authors: Michael M Wollring, Jan-Michael Werner, Elena Bauer, Caroline Tscherpel, Philipp Lohmann, Gabriele Stoffels, Christoph Kabbasch, Roland Goldbrunner, Gereon Fink, Karl-Josef Langen, Norbert Galldiks
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND This study evaluates O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET and contrast-enhanced MRI for early response assessment in glioma patients at recurrence treated with lomustine-based chemotherapy. METHODS Thirty-six adult patients with WHO CNS Grade 3 or 4 gliomas (glioblastoma, 69%) at recurrence (median number of recurrences, 1; range, 1-3) were retrospectively identified. Besides MRI, serial FET PET scans were performed at baseline and early after chemotherapy initiation (median number of cycles, 2). Mean and maximum tumor-to-brain ratios (TBR), metabolic tumor volumes (MTV), the occurrence of new distant hotspots with a mean TBR &amp;gt; 1.6 at follow-up, and the dynamic parameter time-to-peak were derived from all FET PET scans. Threshold values of PET parameters were defined using receiver operating characteristic analyses to predict progression-free survival (PFS) of ≥ 6 months and overall survival (OS) of ≥ 12 months. MRI response assessment was based on RANO criteria. Using univariate and multivariate survival estimates, the predictive value of FET PET parameters and RANO criteria were subsequently evaluated. RESULTS After treatment initiation, the median follow-up time was 11 months (range, 3-71 months). Relative changes of the mean and maximum TBR, MTV, and RANO criteria predicted a significantly longer PFS (all P&amp;lt; 0.003) and OS (all P&amp;lt; 0.05). At follow-up, the occurrence of new distant hotspots (n≥ 1) predicted a worse outcome, with significantly shorter PFS (P=0.001) and OS (P&amp;lt; 0.001). Changes of the dynamic parameter time-to-peak did not predict a significantly longer PFS or OS (P &amp;gt; 0.05). Multivariate survival analyses revealed that new distant hotspots at follow-up had the highest significance level to predict non-response (P&amp;lt; 0.001; hazard ratio, 8.578), independent of RANO criteria, IDH mutation status, and O6-methylguanine-DNA-methyltransferase promoter methylation. CONCLUSIONS FET PET seems to be a powerful tool for identifying responders to lomustine-based chemotherapy early after treatment initiation.
MODL-34. DECELLULARIZATION OF HUMAN AUTOPSY BRAIN TISSUE TO GENERATE A 3D EXTRACELLULAR MATRIX FOR MEDULLOBLASTOMA AND ATYPICAL TERATOID/RHABDOID TUMOUR MODELLING
Authors: Phoebe McCrorie, Harry Porter, Jeffy Vinohar, Mohammed Diksin, David Scurr, Ruman Rahman
Journal: Neuro-Oncology (2022)

Abstract INTRODUCTION Childhood medulloblastoma (MB) and atypical teratoid/rhabdoid tumours (AT/RT) are malignant brain tumours occurring in the posterior fossa, for which prognoses remains particularly poor for the MB Group 3 subtype characterised by amplification of the Myc oncogene and for AT/RT in general. Current in vitro models for these neoplasms rely on non-coated plastic, various hydrogels, or animal-derived extracellular matrix (ECM), which fail to recapitulate the physiological environment from which the cells are derived from. METHODS We have developed a method to decellularize ex vivo human brain tissue from different anatomical locations for the use in 3D in vitro models. Human cerebellar brain tissue was harvested from autopsy brain and sectioned into small cubes before bathing in a sodium dodecyl sulfate/phosphate-buffered saline mixture for several days, before washing and lyophilising. RESULTS The optimised method for generation of decellularized human brain ECM successfully removes nuclei as confirmed by histological staining and DNA quantification (DNA reduction of ≥ 60%). Orbitrap-Secondary Ion Mass Spectrometry analysis confirmed the retention of the ECM components laminin (C9H11N3O2Na+), fibronectin (C9H14N4O2Na+ and C20H33N7O5Na+) and collagen (C4H5N2O2+), with a reduction in cell membrane lipid components (glycerophosphocholine, C9H19NPO4+; phosphocholine, C5H15NPO4+; and choline, C5H14NO+) relative to control tissue, with a &amp;lt; 2 ppm accuracy, which was further corroborated by glycosaminoglycan and collagen assays. Multiple molecular subtype-specific AT/RT and MB cell lines have been successfully grown on decellularized cerebellar-ECM/PEGDA hydrogel, showing no reduction in metabolic viability using PrestoBlue and Cell Titer Glo assays. CONCLUSIONS This methodology offers an innovative human-only high-throughput 3D drug screening model, whereby patient-derived MB or AT/RT cells are co-cultured with healthy human cerebellar astrocytes upon decellularized cerebellar ECM, which we term ‘Tumoursphere Matrices’.
MODL-33. AN ANIMAL MODEL OF GLI2-AMPLIFIED MEDULLOBLASTOMA
Authors: Najiba Murad, Xiao Liu, Ran Tao, Yanxin Pei
Journal: Neuro-Oncology (2022)

Abstract Medulloblastoma (MB) is the most common malignant brain tumor affecting children. Among the known subtypes of MB, GLI2-amplified SHH-MB associated with P53 mutations has the worst prognosis, and a 5-year survival rate of less than 30%. Moreover, GLI2-amplified MBs are non-responsive to SMO inhibitors, the only targeted treatment option available for SHH-MB. To address this treatment gap, there is an urgent need to identify novel potential therapeutic targets, an effort that requires better understanding of key cellular and molecular mechanisms underlying GLI2-amplified MB. To that end, we generated a mouse model of GLI2-amplified MB and identified GL12 as the critical driver of tumorigenesis, and granule cell progenitors (GCPs) as the cells of tumor origin. We further found that GLI2 specifically drives embryonic, but not neonatal, Math1+ GCPs to form SHH-MB tumors. An scRNA-seq analysis revealed MAPK pathway activation specifically in embryonic Math1+ GCPs. The MAPK pathway was activated in mouse and human GLI2-driven MB tumors, and a MEK/ERK inhibitor significantly inhibited GLI2-driven MB in vivo. Based on these findings, we hypothesize that GLI2-driven MB originates from a specific population of Math1+ GCPs during a discrete temporal interval in cerebellar development, and that targeting MAPK/MEK/ERK pathway components represents a novel approach to treatment of GLI2-amplified MB.
CNSC-29. INVESTIGATING THE INFLUENCE OF DOPAMINERGIC ACTIVITY ON THE GLIOBLASTOMA NICHE
Authors: Matthaeus Ware, Luiza Lopes Pontual, Chunying Yu, Michelle Kushida, Naghmeh Rastegar, Sonam Dolma, Peter Dirks
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma (GBM) is an incurable disease of adults and children and the deadliest form of central nervous system (CNS) malignancy. Despite major advances in our understanding of GBM biology in recent years, the prognosis for patients who develop this disease has not improved. If we hope to find new treatments for GBM that are safe and effective, we desperately need to reform our thinking. The brain’s chemical milieu is rich with neurotransmitters, and our lab’s screen of 680 neuroactive compounds on patient-derived glioblastoma stem cells (GSCs) in vitro strongly implicates neurotransmitter pathways as critical regulators of the GSC niche. More specifically, disrupting dopamine signaling by inhibiting its receptor D4 on GSCs causes substantial GSC apoptosis in vitro and attenuates GBM growth in vivo (Dolma et al., Cancer Cell, 2016). Dopamine (DA) is a catecholamine neurotransmitter that is essential for reward learning and movement and has numerous roles in cognition. Consequentially, dysregulation of DA signaling is associated with a diversity of brain diseases ranging from drug addiction to schizophrenia to Parkinson’s. Our research aims to determine how DA signaling affects normal neural stem cell (NSC) and tumorigenic GSC populations, as we hypothesize that GSCs arising/residing in DA projection zones exploit dopaminergic (DAergic) activity for GBM growth. Toward these aims, we have developed in vivo model systems and harnessed them to study NSC and GSC niches in the context of either controlled activation or depletion of DAergic neurons. These manipulations of the brain's DAergic neurons are achieved using optogenetic stimulation, genetic depletion, and neurotoxin-mediated ablation in mice. Ultimately, unraveling the dopaminergic influence on GBM may contribute to a redeployment of existing treatments—that modulate DA signaling and are already approved to treat CNS disorders—to patients with this deadly brain cancer.
CCRG-03. STUDY OF PIWI-INTERACTING RNAS IN GLIOBLASTOMA PATHOLOGY: A NEW LEVEL OF REGULATION OF GLIOBLASTOMA STEM CELLS?
Authors: Pavel Fadrus, Vaclav Vybihal, Frantisek Siegl, Martin Smrcka, Ondrej Slaby, Jiri Sana
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND One of the putative mechanisms of early recurrence of GBM is the existence of glioblastoma stem cells (GSCs) that can resist therapy and subsequently establish new GBM foci. PIWI-interacting RNAs (piRNAs), responsible for maintaining genome stability, may then play a key role in their biology, particularly in germ and stem cells. A number of piRNA molecules are also promising biomarkers useful for prognosis and prediction of disease progression.Material and METHODS Glioblastoma stem cells were cultured in DMEM/F12 medium supplemented with bFGF and EGF growth factors. DMEM medium containing 10% fetal bovine serum (FBS) was used to culture differentiated cells. RNA was isolated from the selected paired primocultures and subsequently checked for quality by capillary electrophoresis. NEBNext Small RNA Library Prep Set was used for the preparation of cDNA libraries. Sequencing analysis was performed using the Next500/550 High Output v2 Kit for 75 cycles and the NextSeq500 sequencer. RESULTS Twenty paired primary cultures were prepared to verify the expression of CD133 and SOX2 in GSCs, the ability to establish tumors in immunodeficient mice, and the ability to differentiate. At this time, we finished sequencing of piRNA molecules and acquired data are bioinformatically analysed. Subsequently, we will perform analysis of selected piRNAs to be diagnostic and prognostic biomarkers on the GBM samples and non-tumor brain controls. All results will be presented at the conference. CONCLUSION Based on recent studies, it is evident that piRNA expression can have a significant impact on GBM biology. Their expression within GSCs may then provide a tool for identifying and targeting these cells and could be usable as a diagnostic and prognostic biomarker in GBM patients.The study was supported by the programme project of the Ministry of Health of the Czech Republic with reg. no. NV19-03-00501, NV19-03-00559, Conceptual development of research organization FNBr, 65269705
EXTH-98. ENHANCING T CELL TRAFFICKING OF CD3-ENGAGING IMMUNOTHERAPY TO TUMORS OF THE CENTRAL NERVOUS SYSTEM
Authors: Kirit Singh, Matthew Foster, Kelly Hotchkiss, David Snyder, Mustafa Khasraw, John Sampson
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Effective immunotherapy against tumors of the central nervous system (CNS) requires that the drug the blood brain barrier (BBB) and encounter immune cells. We have previously described a mechanism which may facilitate transport of CD3-engaging therapeutics into the CNS, via carriage on activated T cells. Building on this, we sought to produce specific T cell phenotypes that rapidly enter and accumulate in the CNS. METHODS 8–10-week-old C57/Bl6 mice (n=5-6 per group) were implanted with 30,000 CT2AvIII cells which established over 14 days. Mice received (1) CD45.1 lymphocytes activated with IL-7 and Concanavalin-A (single intravenous (IV) injection, 1 x 107 adoptive lymphocyte transfer (ALT)) or (2) CD45.1 lymphocytes activated with IL-2 and serial Con-A stimulation. Mice were sacrificed 3 hours following ALT and their brains analysed via flow cytometry. A follow-up timepoint of 48 hours was also analysed. Groups were compared using a Mann-Whitney U test. RESULTS Ex vivo culture in group 1 yielded a mixed population of T effector and T central memory cells whereas group 2 resulted in terminally differentiated T effector memory cells only. VLA-4, a migratory integrin involved in T cell entry into the CNS was upregulated in the IL-7 group. Mice in Group 1 demonstrated significantly enhanced entry of CD8+ effector and memory T cells into tumor bearing hemispheres 3- and 48-hours following administration compared to Group 2 (p = 0.005, p = 0.0159 respectively). CONCLUSIONS Varying the cytokine cocktail used for ex vivo activation and expansion of T cells results in markedly different trafficking properties and phenotype composition. Ongoing work will determine how enhanced T cell localization to tumor affects accumulation of immunotherapy via the hitchhiking mechanism. Further, we will evaluate the safety of combinatorial CD3-engaging immunotherapy and ALT in Phase I trials (NCT04903795) using a cGMP Brain Bi-specific T cell engager (BRiTE).